RESTATED AMENDMENT #10
                            TO THE SECOND AMENDED AND
                           RESTATED PURCHASE CONTRACT

                  THIS RESTATED AMENDMENT #10 TO THE SECOND AMENDED AND RESTATED
PURCHASE  CONTRACT (the "Restated  Amendment  #10") is entered into on this 10th
day of December,  1996 by and between  International Private Satellite Partners,
L.P.,  d/b/a Orion  Atlantic,  L.P.,  a Delaware  limited  partnership  with its
principal offices located at 2440 Research Boulevard, Rockville, Maryland 20850,
United  States of America  ("Orion"),  and Matra  Marconi  Space UK  Limited,  a
company  organised  and  existing  under the laws of England  and Wales with its
Registered  Office at The Grove,  Warren  Lane,  Stanmore,  Middlesex,  HA7 4LY,
England (the "Contractor").

                  WHEREAS,  Orion Satellite  Corporation,  as General Partner of
Orion, and British  Aerospace  Public Limited Company ("BAe"),  entered into the
Second Amended and Restated Purchase Contract, dated 26 September 1991 (together
with all amendments thereto, the "F1 Contract");

                  WHEREAS,  the F1  Contract  was  assigned  by  BAe to  British
Aerospace Space Systems Limited,  the name of which was subsequently  changed to
MMS Space  Systems  Limited  after its  acquisition  by Matra  Marconi  Space UK
Limited;

                  WHEREAS,  the parties have reached a revised  agreement on the
terms under which certain incentive payments will be made;

                  WHEREAS,  the parties  previously entered into Amendment #9 to
the F1 Contract under which the conditions  precedent to Orion's obligations did
not occur;

                  WHEREAS,  the parties previously entered into Amendment #10 to
the F1 Contract  (the  "Original  Amendment  #10")  under  which the  conditions
precedent to the effectiveness of that Amendment did not occur;

                  NOW, THEREFORE, in consideration of the above premises and the
mutual  covenants  and  agreements  contained  herein,  and for  other  good and
valuable consideration, the receipt of which is hereby acknowledged, the parties
hereto (hereinafter, the "Parties") agree as follows:

                  1.  DEFINED  TERMS.   Except  as  otherwise   defined  herein,
capitalized  terms used herein and not otherwise defined shall have the meanings
ascribed to them in the F1 Contract.

Restated Amendment #10

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                  2.  AMENDMENT  #9.  Amendment #9 is terminated in its entirety
and shall be of no force and effect.

                  3.  AMENDMENT   #10.    The   conditions   precedent   to  the
effectiveness  of Original  Amendment  #10 did not occur and,  accordingly,  the
Original Amendment #10 shall be of no force and effect.

                  4.  CONDITION  TO  EFFECTIVENESS  OF THIS  AMENDMENT.  Orion's
obligations under this Restated Amendment #10 shall become effective when (i) an
Option Agreement to purchase the ORION 2 Spacecraft constructed and delivered in
accordance with the ORION 2 Purchase Contract,  as to be amended,  between Orion
and  Contractor  (the  "Option  Agreement")  is in  effect  and  (ii)  at  least
$25 million in Option  payments have been made by Orion to Contractor.  The date
upon which this Restated  Amendment #10 becomes  effective is herein referred to
as the "Effective Date".

                  5. ORION  COVENANT AS TO PAYMENT.  Orion hereby  covenants and
agrees that, without the Contractor's  consent,  it shall not, after the date of
this Amendment,  subordinate the payments required to be made hereunder or under
Articles 15.6.1 and 15.6.2 of the F1 Contract (the  "Incentives") to the payment
of the  principal of or the interest on any new debt  incurred or  guaranteed by
Orion or any  affiliate  of ORION or to the payment of any  obligation  incurred
with respect to the Spacecraft provided under the F1 Contract.  On the Effective
Date,  Orion shall provide to the Contractor  Orion's  representation  verifying
that no such subordination  occurred between the date of this Restated Amendment
#10 and the Effective Date.

                  6. PAYMENT OF INCENTIVE: PURCHASE OF DEBENTURES

                  (a) On the Effective  Date,  Orion shall pay to the Contractor
by wire transfer into a bank account established by the Contractor in the United
States of America,  the details of which account shall be made known to Orion at
least two (2) weeks prior to the Effective  Date,  $13,000,000 of the Incentives
due and payable on such date.

                  (b) On the  Effective  Date,  the  Contractor  shall  purchase
$10,000,000  aggregate principal amount of those Debentures issued by ONS or any
ONS  affiliate,  provided  that Orion makes the  payment  required to be made by
Section  6(a).  The  Debentures  shall have terms  identical  to those issued to
British Aerospace Public Limited Company (or any affiliate thereof).

                  (c) Orion shall pay the difference  between the Incentives due
and payable on the Effective Date and  $13,000,000 on the last day of the Option
Period (as defined in the Option Agreement).

                  (d) Orion shall pay all of the  remaining  Incentives  as they
become due in accordance with the payment schedule in Articles 15.6.1 and 15.6.2
of the F1 Contract.

Restated Amendment #10

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                  7.    ADDITIONAL PROVISIONS.
                        ---------------------

                  (a) In the event of any  inconsistency  between this  Restated
Amendment #10 and the remaining provisions of the F1 Contract, the terms of this
Restated Amendment #10 shall govern.

                  (b) This Restated Amendment #10 may be executed by the Parties
hereto  in two or more  counterparts,  each of which  shall be  deemed  to be an
original  instrument  but all of which  shall be  deemed  to be one and the same
instrument.

                  (c) Contractor  hereby waives and releases any  materialman's,
mechanic's  or other liens it may have with  respect to any of the  payments due
hereunder.

                  (d) This  Restated  Amendment #10 shall be governed by the law
of the State of Maryland, U.S.A.

                  IN WITNESS  WHEREOF,  the Parties have each duly executed this
Restated Amendment #10 as of the day and year first written above.

INTERNATIONAL PRIVATE                                MATRA MARCONI SPACE
SATELLITE PARTNERS, L.P.                             UK LIMITED

By:  Orion Satellite Corporation,
     Its General Partner


By:  /s/W. Neil Bauer                                By: /s/Armand Carlier
     ----------------------------                        -----------------------
     W. Neil Bauer                                       Armand Carlier
     President


Restated Amendment #10